The invention relates to a conching device for treating chocolate paste by kneading and mixing, comprising a trough wherein at least one rotor with refining tools rotates.
Conching devices may be designed as dry conching devices or as liquid conching devices. It is preferred to use conching devices that can be operated both as dry conching devices and liquid conching devices. With such a conching device as it has become known from DE-A 36 26 732, refining tools with refining blades extending at a slant angle to the trough wall are provided, which refining tools serve as scrapers or wipers for the dry treatment when the direction of rotation is reversed. The conching devices can have only one rotor in a trough compartment assigned to it, or else a plurality of rotors in trough compartments respectively assigned to them.
When a conching device is employed which, by changing the direction of rotation of the rotors, can be operated both as a dry conching device and as a liquid conching device, the chocolate paste will first assume a dry-pasty condition, whereupon it will turn into a viscous-plastic condition to finally change into a liquid condition. With such a conching of the chocolate paste by means of the mechanical action of the rotors, a heating and an aeration will be accomplished. When using this arrangement, for example a volatilization of organic acids, such as acetic acid, and also a desired oxidation of flavorings will result. Moreover, a mixing effect and a rounding off of the particles will be achieved.
The air required for the aeration reaches the chocolate paste through an opening in the upper wall of the trough. The evaporated substances escape from the trough out of this opening. Apart from this desired exchange through the opening of the trough, also chocolate paste is thrown out of the trough due to the mechanical action of the rotors. Since fine chocolate masses have to be conched up to 48 hours, they will often show completely different viscosities although being of identical recipe and exhibiting the same temperatures and comminution rates, which may result in some amount of chocolate paste being thrown out of the trough. The ensuing cleaning of the outer parts of the conching device then requires a great expenditure of time and energy. It is true that vertical plates are provided in the area of the trough opening, but these plates are unsatisfactory in most cases as they prevent the spurting of the chocolate paste only partially and also because they have a considerable soiling effect and have to be cleaned manually.